I am having the followingn problem, which I will describe in a
scenario. In my working copy, I changed files A, B and C and then
commited the changes. I then realized that file A should not have been
changed. I cannot figure out how to undo the change.

What makes the most sense to me is to issue
"svn update --revision PREV A"
in my working copy. However, although my working copy is in the
state that I want the repository to be after this command, "svn commit"
now failes silently.

Am I going about this all wrong? Or is this a bug, and svn commit
out to do something, or at least give me a message telling me what I did
wrong?